Method and apparatus for finishing workpieces under high vibrating pressure (tentative)

ABSTRACT

A method and an apparatus for finishing workpieces which are caused to flow in a helical motion together with abrasive media within a circular vibratory finishing tub in the form of a hollow annulus closed at both ends, and more particularly for vibratory finishing of workpieces together with abrasive media in a heavily compressed condition and for separating the mass (a mixture of workpieces and abrasive media) into workpieces and abrasive media. The apparatus has a downwardly inclined or horizontal circular vibratory finishing tub having an opening at the top which is closed in operation, in the form of a hollow annulus, having the radially greatest sectional area at the central portion thereof and the sectional area being gradually smaller toward both ends thereof, so that the mass is caused to flow during vibration with an increased density resulting in a substantially compressed condition of the mass so that workpieces and abrasive media are caused to move in a closely spaced relation which would otherwise be eliminated at every vibrating. By this arrangement the vibrating pressure and action between workpieces and abrasive media are improved and the mass separating efficiency as well as the smoothness of the finished surfaces are also improved considerably.

United States Patent Kobayashi 1 Aug. 5, 1975 l METHOD AND APPARATUS FORFINISHING WORKPIECES UNDER HIGH |57| ABSTRACT VIBRATING PRESSURE(TENTATIVE) A method and an apparatus for finishing workpieces Illlvfimfll'i Hisflmine Kfibayashit N g ya. apan which are caused to flowin a helical motion together [73] Assigncci Shikishima Timon Mfg Co Lidwith abrasive media within a circular vibratory finish- Nagoya Japan mgtub In the form of a hollow annulus closed at both ends, and moreparticularly for vibratory finishing of l Fllcdi P 1973 workpiecestogether with abrasive media in a heavily [2| I App No: 351966compressed condition and for separating the mass (a mixture ofworkpieces and abrasive media) into work pieces and abrasive media. Theapparatus has a downl Foreign pp n Priority D lfl wardly inclined orhorizontal circular vibratory finish- Apr. I7, 1972 J'tlplll'l 47-38474ng ub having an Opening at the top which is closed in operation in theform of a hollow annulus, having the [52] U.S. Cl. .I 5l/l63 ra iallygreatest sectional area at the central portion [51 1 Int. Cl .I B24b31/06 h r of n h sec ional re eing gradually smaller [52%| Field of Searh 5 h3 7; 241/175 toward both ends thereof. so that the mass is causedto flow during vibration with an increased density result- [56]References Cit d ing in a substantially compressed condition of theUNITED STATES PATENTS mass so that workpieces and abrasive media are 324l l 2o 5/1966 Fosscn I. 5m x caused to q m u.cl.osely Spaced i wh'chLena-267 H971 Huhncrnm H63 would otherwise be eliminated at every vibratng By molly) 4/w74 Ftfill'itrll. .4 52/163 this arrangement theVibrating Pressre and acllo" tween workpieces and abrasive media areimproved FOREIGN PATENTS OR APPLICATIONS and the mass separatingefficiency as well as the 224,(|5u 3/l97l United Kingdom 5l/l63smoothness of the finished surfaces are also improved Primary I;.\'umim'rHarold Di Whitehead Armrm'r Agcn1 u! FirmWenderoth, Lind &Ponack considerably.

9 Claims, 8 Drawing Figures PATENTEU AUG 51975 SHEET Fig.7

PRIOR ART PATENTEU 5195 $2,897, 658

SHEET Fig 8 PRIOR ART f 1 4 51c1912a12 1 METHOD AND APPARATUS FORFINISHING WORKPIECES UNDER HIGH VIBRATING PRESSURE (TENTATIVE)BACKGROUND OF THE INVENTION In a conventional finishing apparatus havinga circular vibratory finishing tub, the finishing operations areperformed with the tub open at the top to facilitate a visual inspectionof the flowing mass. However, this causes the disadvantages of limitingthe volume of workpieces which can be finished, causing damage ordefects to the workpieces due to the impact thereof with each other, themedia and the tub under strong vibration and reducing the massseparating efficiency due to the backflow of the mass.

There are conventional finishing apparatuses having a circular vibratoryfinishing tub, a rotary barrel or mill, a centrifugal barrel, or avibratory finishing tub or box type in which the barrel or the like isclosed in operation. However, all of those apparatuses provide only ameans of closing the barrel or the like without which it would beimpossible to operate the apparatus since the contents would otherwisebe easily vibrated out, or a means of closing the barrel or the like toprevent water from the finishing compound from spattering out. In otherwords, this is simply a covering means, but not a means of finishingworkpieces effectively by vibration under a heavily compressed conditionas in this invention.

SUMMARY OF THE INVENTION With the method and apparatus according to theinvention, an increased volume of workpieces can be finished, and thesmoothness of the finished surfaces of workpieces is improved by placingthe workpieces and abrasive media under a heavily compressed conditionduring vibration.

In order to meet these needs, the apparatus has a circular vibratoryfinishing tub having an opening at the top which is closed in operation,and has the radially greatest sectional area at a central portionthereof before a dam and the radially smallest sectional area at thatportion thereof beyond said dam.

Consequently, contents of the mass are caused to move in a closelyspaced relation, and are mutually subjected to a heavy force by thevibration while passing through the portion of the smallest sectionalarea.

According to the invention. the tub is a downwardly inclined orhorizontal circular vibratory finishing tub in the form of a hollowannulus having an opening at the top which in operation is closed,having the radially greatest sectional area other than the massseparating portion, at that portion thereof before a dam and a sectional area which is gradually smaller toward both ends thereof. one endhaving the smallest sectional area at that portion beyond or downstreamof the dam and the other end having a medium sectional area at thatportion connected to the mass separating portion, so that contents ofthe mass are caused to move in a closely spaced relation and are thussubjected to a heavy force by the vibration while moving inside the tub.

Consequently, it is possible to handle double the volume of the mass andimprove the smoothness of the finished surfaces by reducingsubstantially by half the roughness thereof. This can thus protectworkpieces from damage or defects due to the impact thereof with eachother, the media or the apparatus. Furthermore,

these increased volume and improved smoothness bring the finishingefficiency to substantially four times that of the conventionalapparatus. In using the ma chine for a mill, not only can the deviationof the milled particles from the desired sizes can be reduced, but theefficiency can be increased. This finishing efficiency cannot beobtained from the prior art vibratory finishing apparatuses for handlingmetals or ores or the like. In other words, these prior apparatuses areusually capable of increased efficiency for polishing, milling andmixing purposes, but for that increase must sacrifice the smoothness ofthe finished surfaces.

According to this invention, it is possible not only to increase thevolume of the processing mass but also to improve the finishingefficiency and smoothness of the finished surfaces.

As has been described heretofore, the invention provides an improvedfinishing efficiency by increasing the smoothness of the finishedsurfaces, and also a reduction of substantially half the amount ofdeviation of the milled grain sizes from the desired sizes, in additionto an increased volume of workpieces which can be finished. Thus, itprovides a completely novel performance by bringing the whole efficiencyto substantially four times that of the prior art.

When the mass is fed by a charge port into the tub of the presentapparatus, it is subjected to vibration and is caused to travel in ahelical motion. During the finishing operation, the mass is caused tomove upwardly along the dam and when the operation is completed, it iscaused to move up to a sieve along a movable flap which has been moveddownwardly and on the sieve the mass is separated into workpieces andabrasive media. The abrasive media is again fed through the sieve intothe tub by action of gravity.

This invention is characterized in that the circular vibratory finishingtub having an opening at the top to be closed in operation comprises twoportions with radially different sectional areas, so that the mass iscaused to move inside the tub under a heavy compression force by thevibration.

As compared with the conventional apparatus having a vibratory finishingtub open or closed at the top by which the mass is uniformly subjectedto vibration, the apparatus according to the invention is provided witha circular vibratory finishing tub having the radially greatestsectional area at that portion before the dam and the radially smallestsectional area at that portion over said dam, so that the mass flowingunder vibration toward the smallest sectional area is subjected tocompression from the barrel wall and substantially heavy compressionforce by vibration. When it is supposed that the greatest sectional areaat that portion before the dam is E. the smaller sectional area at theportion after the mass separating portion F should preferably be smallerthan F. but greater than 0.8 E, the optimum being more or less 0.9 E.Then, suppose the smallest sectional area is G, G should be within therange of 0.9 E G 0.5 E. the optimum being within the range of 0.8 E to0.6 E.

Consequently, it is possible to obtain a considerably improved finishingefficiency by controlling values of these two sectional areas inside thetub.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIG. 1 is a front view ofone apparatus according to this invention.

FIG. 2 is a plan view of the apparatus of FIG. 1.

FIG. 3 is a fragmental developed sectional view taken along the line A Aof FIG. 2.

FIG. 4 is a front view of another apparatus according to this invention.

FIG. 5 is a plan view of the apparatus of FIG. 4.

FIG. 6 is a sectional view taken along the line B B of FIG. 1.

FIG. 7 is a front view of one conventional apparatus.

FIG. 8 is a front view of another conventional apparatus.

DETAILED DESCRIPTION OF THE INVENTION According to the invention. a damis provided to separate a circular vibrating finishing tub into twoportions, one having the radially greatest sectional area and the otherhaving the radially smallest sectional area. so that the mass movinginside the tub can be finished or milled by vibration under a heavycompression force with a substantially improved efficiency.

In the drawings, in FIGS. 1 and 2 is shown the upper end I of a circularvibratory finishing tub placed in a downwardly inclined position asshown in FIGS. 1 and 2. The tub has a descending part 1a. an ascendingpart lb. and a separating part It, respectively.

In FIGS. 4 and 5 as shown a circular vibratory finishing tub 21, 21aplaced in a substantially horizontal position. which has an ascendingpart 2112 and a separating part 21c.

For the convenience of reference. two conventional apparatuses having acircular vibratory finishing tub open at the top are shown in FIGS. 7and 8. In FIG. 7 the upwardly inclined tub has a lower end 41 open atthe top, and ascending part 41a, an ascending part 4th over the dam anda separating part 410.

In FIG. 8, a horizontal circular vibratory finishing tub 51, 51a is openat the top and has an ascending part 5112 over the dam and a separatingpart 510.

By referring to the reference numerals common to all drawings. we willillustrate the structure of the appara- The circular vibratory finishingtub is rigidly secured by a rib 3 to a flange 2 and mounted by aplurality of springs 5 on a pedestal 4. An electric motor 9 isvertically fixed to a flange 8 within a cylindrical housing 7.

When the motor 9 is started, it causes weights It), 10 rigidly securedto the motor shaft to rotate and then vibrate the tub and the masstherewith. A superposed portion 11 is provided for the descendingportion of the tub of FIGS. 1 and 2, and for the ascending portion ofthe tub of FIG. 7. respectively.

A dam I2 is rigidly secured on said superposed portion II. A dam is alsoprovided for the horizontal tub of FIGS. 4 and 8. This dam is preferablyof an angular shape having an ascending part 12 and a descending part12a. A dam having only one plate may be provided vertically. or onlythat portion of the angular-shape dam facing the flow direction of themass may be provided with an ascending part.

Apart from the shape of the dam. the most important thing of theinvention is that the ratio of the sectional area at one point to thatat the other point inside the tub should be maintained within the rangeof a given value.

By the structure of the invention. it is possible to cause the mass totravel smoothly inside the tub and to reduce the vibrating width oramplitude of the mass to a small amount by increasing the density of themass. thus subjecting the mass to heavy compression force duringvibration.

A cover 6 encloses a plurality of helical springs S. A movable flap I3is placed in such a position that it does not prevent movement of themass. indicating a position which the flap I3 takes in turning on itsshaft 14 when the mass is being separated. A sieve 15 is provided forseparating the mass. A mass charging port 16 is provided with a cover16a having a grip 1617. In operation. the port I6 is closed by the cover16a. This port 16 is provided as indicated in FIG. 1 near to thatportion of the tub where the mass is entering the finishing portionafter passing through the separating portion.

When the mass is fed through the port 16 into the tub, it is subjectedto vibration. flowing in a helical motion in the direction of the arrow17b revolving inside the tub as indicated by the arrows l7 and 170.Then. the mass moves up along the dam as indicated by the arrow 18 andcontinues to flow beyond the dam as indicated by the arrow 19, where themass receives the finishing operations.

When the finishing operations are completed. the flap 13 rotates on itsshaft to the position as indicated by dot-dash lines 131: of FIGS. I and3 to move the mass up to the sieve I5 where the mass is separated intoworkpieces and abrasive media. The media are screened through the sieveto be fed again into the tub. The finished workpieces are automaticallyejected out of the tub as indicated by the arrow 20.

For the circular vibratory finishing tub open at the top as shown inFIGS. 7 and 8. there is no need of such a port for charging a mass.Motors. weights. and other component parts that are the same as in FIG.I are not indicated in FIGS. 7 and 8, but naturally these are alsoinstalled on the apparatus of FIGS. 7 and 8.

The invention is particularly characterized in that the circularvibratory finishing tub comprises one portion before the dam having theradially greatest sectional area and one portion over the dam having theradially smallest sectional area. so that the mass is caused to moveunder a heavy compression force during vibration. In the conventionalapparatus having a circular vibratory finishing tub. open or closed atthe top. vibration of the mass is caused uniformly. Accordingly to theinvention. however. a circular vibratory finishing tub is provided inthe form of a hollow tubular container having a gradually smallersectional area toward both ends. having one portion before the damhaving the radially greatest sectional area, one portion over the damhaving the radially smallest sectional area. and one portion connectingto the separating portion having a radially medium sectional area. sothat the vibration given to the whole exerts on the mass a substantiallycompressing force. The mass is thus caused to move under such heavycompressing force during vibration.

The widths E'. F. G of the tub at the various portions except theseparating portion are the same as indicated in FIG. 2. The portion F ofthe tub before the dam hits the greatest in depth. and the depth ofportion F after the separating portion should be smaller than E andgreater than 0.8 E. the optimum being more or less 0.9 E. The depth ofportion G over the dam should preferably be (1.9 E G 0.5 the optimumbeing within the range of 0.8 E to (1.6 E, namely E F G and accordinglyEE' FF' GG'.

When the tub and the mass therein are subjected to vibration, i.e., avibration equivalent to about 6 mm is amplitude, the vibrating width oramplitude is compressed so as to be substantially smaller than 6 mm andgreater than 3 mm. In the conventional apparatus of this type, theamplitude generally ranges from 8 mm to 3 mm but in this invention, itis possible to obtain an amplitude of6 mm to 2 mm by compressing it by lmm to 3 mm. In this way, workpieces can be polished or finished underheavy compression force during vibration. The vibration thus obtaineddiffers greatly from that of the prior art in the finishing efficicncy,since the former offers substantially four times higher performance thanthe latter.

As a result, it is possible to improve the finished surfaces ofworkpieces, doubling the efficiency for finishing workpieces andreducing the deviation of the sizes of milled grain from the desiredsize. This equals four times higher finishing efficicncy, which isevident from the tables I to 4 that follow hereinafter.

As can be seen from the above tables, the finishing efficicncy of theinvention differs greatly from that of the conventional apparatus. whichis due to the fact that the inner diameter D of the outer periphery ofthe tub and the outer diameter d of the inner periphery thereof have acommon size, respectively, in all types,

the inside arcuate bottom being uniform, and that the radially sectionalportions.

E, F'and G have the same width, while these portions have radiallydifferent sectional areas depending on the depth E, F and G thereof.

In the embodiments of the apparatus according to this invention, supposethe portion E is I, then the portions F and G should be E F 0.8 and Eand 0.9 E G 0.5 E, respectively, resulting in E F G.

In this way, when the mass is charged in an amount sufficient to fillthe greatest sectional space ahead of the darn it will thus becompressed in moving from the portion F toward the portion G over thedam having radially the smallest sectional area. However, in theapparatus according to one embodiment of the prior art (FIG. 7), E, F,and G are equal while in the apparatus according to the other embodimentof the prior art (FIG. 8), Fa, E, F and G are different and Fa E F G,the portion E note being the greatest in sectional area in thisapparatus.

It is clear that the structure of these portions E, F, and G of theconventional apparatus differs from that of the apparatus of theinvention.

According to the apparatus of the prior art, the structure and functionare not such as to compress the moving mass during either the finishingor separating operations. Because of this, higher inner walls must beprovided for the inner and outer peripheries of the tub so as to preventthe overflow of the mass moving onto the stationary and movable damsduring the separating operations. This causes the mass to flow backward,resulting in a considerably decreased separating efficiency and morefrequent damage or defects due to the impact thereof.

According to this invention, however, the two portions ahead of and overthe dam are provided with a different radially sectional area i.e. E F Gand the ratio among E, F and G is properly determined, so that the massmay be subjected to heavy compression force during vibration, namely thefinishing operations can be performed under a high compression force. Inaddition, this invention can protect workpieces from any type of damageor defect due to the impact thereof, and can also minimize noises sincein operation the tub is closed by a cover.

Tests have been effected under about the same finishing conditions withregard to these four apparatuses, in which three samples of brass, ironand stainless steel have been used. Then, comparison has been made withrespect to the weight of workpieces to be finished and the smoothness ofthe finished surfaces thereof, on the basis of the capabilities of theconventional apparatuses, the results of which have been obtained, asfollows: The weight according to the embodiments of the presentinvention has reached 209 to I53 respectively, as compared with that ofthe conventional apparatus, the surface roughness reaching [.5 to 0.7a.The apparatus of FIGS. I-3 in particular has shown the best results,i.e., a weight of 209 to I53 and the surface roughness of 1.3 to 0.7a.

Table 4 also shows the remarkably significant difference in the millingefficiency between the prior art apparatus of FIG. 7 and that of FIGS.1-3 of the present invention.

In a milling test on bauxite ores (mined in Guinea) using the apparatusof FIGS, [-3 and continuing, the test was continued for 48 hours and inthe resulting material the amount of deviation from the desired particlesize ranged from lOp, to 2p. for 67% and from 60p. to 10p. for 2l% ofthe total amount of material respect vely, whereas in the apparatus ofFIG. 7, the amount of deviation was only within the range of 60a to It)for 47% of the material.

However, in order to make the best use of these efficiencies for thefinishing and milling operations, or for any amount of the massremaining inside the tub, it is desirable to provide a plate H insidethe tub for pre venting the backflow of the mass, as indicated in FIG.6.

When the mass is moving upwardly along the ascending side 12 of the dam,the upper part P of the mass flowing on the inner peripheral side of thetub is apt to flow backward. As the volume of the mass becomes smallerafter further separating operations, the remaining mass is more apt toflow backward.

The ratio in which a given volume of workpieces are mixed with abrasivemedia or the like is usually I to 3 or 2. When workpieces and abrasivemedia are mixed in this ratio, the finishing and separating operationsare more easily performed in the apparatus of the invention. Byproviding the aforesaid plate for preventing the backflow of the mass,it is possible to improve the ratio further, i.e., the ratio of l forworkpieces, and 2 or I for abrasive media. This means that the finishingand separating operations can be improved by substantially 50% and thetime required for the separating operations can accordingly be reducedconsiderably.

Because of the presence of the plate H for preventing the backflow ofthe mass as shown in FIG. 6, the upper part M of the mass M forces themass M to remain on the down stream side (side G of FIG. 4) of the plateH, keeping the mass filling the space between the portions E and G untilthe upper part M moves down to a level N on the upstream side (side F ofFIG. 3) of the plate H. thus enabling the mass to be separated intoworkpieces and abrasive media effectively. At this stage. workpiecesalone are ejected out of the tub.

The volume H of the mass that remains on the up stream and down streamsides of the plate H after completion of the separating operation willbe equivalent to M/2, from which it is evident that the maximumseparating volume MB of the conventional apparatus has been improved bysubstantially fifty percent.

The size. shape and position of installation of the plate H should besuch that it is placed nearer to the portion E along the distancebetween the portions E and G and on the radially inside inner peripheralwall of the tub, having a width of about K/4 and a height of about K (Kis width of the tub), the lower end portion 15 being inclined at anangle (more or less 60 )ohtained by intersecting a line passing throughthe center 0 of a circle K and a perpendicular line U as shown in FIG.6. The plate H should also be such that the major por- Table l tion ofthe inside areuate bottom of the tub is not shut off but open. so as toforce the mass up to the downstream side of the plate H thus preventingthe mass from flowing back from the downstream side to the up- 5 streamside.

In the apparatus of the invention comprising a downwardly inclinedcircular vibratory finishing tub having an opening at the top to beclosed during operation. a separating device is provided at the top ofthe upper portion of the tub indicated by of FlGS. l and 3. The distancebetween the sieve and the bottom of the tub is smaller than the width ofthe tub, which is equivalent to substantially half the distance betweenthe separating device (indicated by 15 of FIGS. 7 and 8) and the bottomof the tub in the conventional apparatus. This makes it possible toavoid occurrence of damage to or defects in the workpieces due to theimpact thereof. also providing a good finishing efficiency for aluminumbronze. zinc diecast and other soft metals.

Finishing Conditions Machine Capacity Frequency Amplitude Advance angleof Sample type cpm lower weight workpiece Disk Shape Quantity Brass.iron. (I IUOL I730 5 5mm 90 stainless mm X titmm 5 each steel (2) I, H HH n a (3) .y n H H n t. H H H H I, H

Charge Abrasive Compound 84 water AES- 3M0 kg GCL Sllg/Sltwaterl TypeDiameter of Tub Depth of Tub Ratio Ratio l 920mm 460mm 240mm l 240mm 124Umm l mrn Ratio (2) 37() l 300 (L81 150 0.68 39H [.05 (3) 231) 207 0.)I41) Ufvl {4) 250 l 200 0.8 lXO ([78 NOTES FOR TABLE 1 I. As the innerdiameter (D) of the outer circumference and the outer diameter (d) ofthe inner circumference are nearly the same for all types. the width E.F and G in the direction of the radius of the arcuate hottom of the tubis almost the same as 2-H) mm. The vertical section in the direction ofthe radius of the tub is 2. F,, denotes an exceptional case for type 3.Type (3) of this invention is superior in almost proportional to thedepth E. F and G of the space inside the tub. except the separatingportion.

(2) in which the depth inside the tub is greater than in E and F.finishing efiicicnc which is clear from the following experimentalresults. Table 2.

Table 2 Experimental Results Finishing Efi'tcieney Typetl) Typetll StockRemoval Brass lron Stainless Brass Iron Stainless Steel Steel mg '4 mgmg ii mg Z mg .i mg "i is! 27.5 13.9 lllll Z8 5 14.2 10.5 2nd 26.9 l5 7ll R 37.2 I49 A I l.7 3rd 28.! I i 9.2 290 l-Lh HI I Average llKl I44llXl Ill} lllll 28] HI? l-lh llll lllb Ill Surface Roughness 2.4;; l l5a 1 F t Itlp. 1 7p TA Bl .E Z (ontinued m: (31 yp Stock Removal Brasslron Stainless Brass lron Stainless Steel Steel mg "/1 mg '7: mg /r mg Zmg Z mg q is! 57.5 25.7 lio 54.6 26.] 14.7 2nd 55.7 28.] m0 57.2 26.5I56 3rd 59.2 28.0 I59 55.8 27.2 l5.0 Average 57,5 209 27.3 I89 l5.8 15355.8 203 26.6 185 l5.l [47 Surface Roughness L3 0,8 (17 1.4;; 0.9;; 0.7

Table 3 Milling Condition Type Sample Media Water Description ShapeQuantity l (alcinated Bauxite Ores Massive 3Ul Alumina Ball l (mined inGuinea) 10,000 to 100p mm 4). 60] (3) 30l 5| NOTES FOR TABLE 3 Note I lType l is a conventional finishing apparatus having an upwardly inclinedcircular vibratory finishing tub with a step open at the top. Model(CL-I00. as sl-mwn in FIG. 7.

2) Type (2) is a conventional finishing apparatus having a horizontalcircular vibratory finishing tub. open at the top. Model CL lOU. asshown in FIG. 8.

3 Type I 3) is a finishing apparatus according to the invention having adownwardly inclined circular vibratory finishing tub. Model CSS-I0O, asshown in FIG. 1, Z and 3.

4) Type 4) is a finishing apparatus of the invention having a horizontalcircular vibratory finishing tub, Model C RS- 100, as shown in FIGS. 4and 5.

The above four types l l to (4) are manufactured by Shikishima TiptonMfg, Co. Ltd. Note 3 The experimental results have been obtained at thelaboratory of this company.

Note 4 Test Time 30 minutes for each finishing test and 48 hours foreach milling test.

Table 4 said tub for closing and charging opening, said finishingportion having an equal width throughout its circum- ExperimentalResults fcrential length and having a depth at said charging MillingEmciency opening and above said dam less than the depth adja- TW: 3;cent the bottom of said dam, and the depth of said finishing portionincreasing gradually from said charging opening to the bottom of saiddam and from the top to Grain 5 to a) 47% z to no, 67% the ot m f i mDisiwrsivn s g 1% lungellhun 12% 2. An apparatus as claimed in claim 1in which the depth E of said finishing portion at the bottom of saiddam, the depth F of said finishing portion adjacent said We claim:charging opening and the depth G above the top of said 1. An apparatusfor vibrating finishing of workpieces dam are in the relationship E F G.under heavy compression force during vibration, com- 3. An apparatus asclaimed in claim 2 in which said prising a substantially horizontallypositioned circular 50 depths are in the relation E F O.8E and annularvibratory finishing tub, a base. a plurality of O.9E G O.5E.

springs on said base and supporting said tub thereon, 4. An apparatus asclaimed in claim 3 in which said vibrating means on said base having adrive means and depth are in the relation F OQE and O.8E G ().6E. avertical shaft having eccentric weights thereon with 5. An apparatusaccording to claim 1 in which the one end connected to said drive meansand other end gs bottom of said tub is downwardly inclined.

connected to said tub, said tub being in the form of a i 6. An apparatusaccording to claim I in which a movhollow annulus having a massseparating portion and a able flap is pivotally mounted above thestationary dam finishing portion extending around the circumference andleaving the space above the dam in the tub open for of said tub from oneend of the mass separating portion flow olthe mass when it is pivotedupwardly and blockofthc other end thereof. a stationary dam in thebottom ing said space above the dam for leading the mass up thereof atthe end of said finishing portion adjacent said out of the tub when itis pivoted downwardly.

other end of said mass separating portion. mass sepa 7. An apparatusaccording to claim 1 in which the rating means in said means separatingportion of said stationary dam has an ascending portion facing uptuhadjacent to and above the level of the top of said stream and adescending portion facing downstream.

stationary dam. said tub having a charging opening in 8. An apparatusaccording to claim 1 in which said the top of said finishing portionadjacent said one end mass separating portion has a sieve in the upperportion of said mass separating portion and a closure means on of saidtub and the distance between the sieve and thc 12 inner peripheral wallof the tub and having u width of KM and at height of K. when K is thewidth of the tub. vertically and radially of the tub. respectively.

1. An apparatus for vibrating finishing of workpieces under heavycompression force during vibration, comprising a substantiallyhorizontally positioned circular annular vibratory finishing tub, abase, a plurality of springs on said base and supporting said tubthereon, vibrating means on said base having a drive means and avertical shaft having eccentric weights thereon with one end connectedto said drive means and other end connected to said tub, said tub beingin the form of a hollow annulus having a mass separating portion and afinishing portion extending around the circumference of said tub fromone end of the mass separating portion of the other end thereof, astationary dam in the bottom thereof at the end of said finishingportion adjacent said other end of said mass separating portion, massseparating means in said means separating portion of said tub adjacentto and above the level of the top of said stationary dam, said tubhaving a charging opening in the top of said finishing portion adjacentsaid one end of said mass separating portion and a closure means on saidtub for closing and charging opening, said finishing portion having anequal width throughout its circumferential length and having a depth atsaid charging opening and above said dam less than the depth adjacentthe bottom of said dam, and the depth of said finishing portionincreasing gradually from said charging opening to the bottom of saiddam and from the top to the bottom of said dam.
 2. An apparatus asclaimed in claim 1 in which the depth E of said finishing portion at thebottom of said dam, the depth F of said finishing portion adjacent saidcharging opening and the deptH G above the top of said dam are in therelationship E>F>G.
 3. An apparatus as claimed in claim 2 in which saiddepths are in the relation E>F>0.8E and 0.9E>G>0.5E.
 4. An apparatus asclaimed in claim 3 in which said depth are in the relation F Congruent0.9E and 0.8E>G>0.6E.
 5. An apparatus according to claim 1 in which thebottom of said tub is downwardly inclined.
 6. An apparatus according toclaim 1 in which a movable flap is pivotally mounted above thestationary dam and leaving the space above the dam in the tub open forflow of the mass when it is pivoted upwardly and blocking said spaceabove the dam for leading the mass up out of the tub when it is pivoteddownwardly.
 7. An apparatus according to claim 1 in which the stationarydam has an ascending portion facing upstream and a descending portionfacing downstream.
 8. An apparatus according to claim 1 in which saidmass separating portion has a sieve in the upper portion of said tub andthe distance between the sieve and the inside bottom of the tub is lessthan the width of the tub.
 9. An apparatus according to claim 1 furthercomprising a plate in said tub for preventing the backflow of the mass,said plate being mounted on inside of the inner peripheral wall of thetub and having a width of K/4 and a height of K, when K is the width ofthe tub, vertically and radially of the tub, respectively.